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aTCA-80302PA/PD
7.2.1 DC PEM Power Distribution
Power distribution within the Shelf originates from each DC PEM and powers all the
blades, the Shelf Managers, the Fan Trays and the SAP. For maximum fault
tolerance, the two DC PEMs should be independently powered by a separate Feed
A and Feed B.
A single DC PEM is capable of supplying the 450 watts of power to each blade
slot and the necessary power for the PEMs, Fan Trays, and Shelf Managers.
If two DC PEMs are in service, each DC PEM is hot-swappable after removing the
power input cables from the DC PEM.
Figure 13: Power Distribution
7.2.2 DC PEM Signals
The DC PEM provides signals for:
• Voltage monitoring
• Current monitoring
• Fuse Monitoring
• Status of the Hot Swap Controller
• Temperature
The I2C devices on the DC PEM board are connected to Master-Only I2C-bus of
the Fan controller board. The Shelf Manager has access to these signals via IPM-
Bus of the Fan Tray.
